v1.3.1 - Multi-Device Sync Fix + Performance + Restore Bug Fix

🔧 Fixed:
- Multi-device JSON sync now works (thanks Thomas!)
- Restore from Server skipped files (timestamp bug)
- No duplicate downloads
- First MD sync after export now fast

⚡ Performance:
- JSON sync: 12-14s → 2-3s
- Hybrid timestamp + E-Tag optimization
- Matches Markdown sync speed

✨ New:
- Sync status UI in MainActivity
- Content-based MD import
- Debug logging improvements
- SyncStateManager for sync coordination

🔧 Technical:
- Clear lastSyncTimestamp on restore
- Clear E-Tag caches on restore
- E-Tag refresh after upload
- Fixed timestamp update after MD export

android/build.gradle.kts

@@ -2,4 +2,6 @@
 plugins {
     alias(libs.plugins.android.application) apply false
     alias(libs.plugins.kotlin.android) apply false
+    alias(libs.plugins.ktlint) apply false
+    alias(libs.plugins.detekt) apply false
 }